A NATIONAL road camera network used to trace wanted criminals has become a "victim of its own success" as police are overwhelmed by information, a watchdog has warned.

Police forces are finding it "virtually impossible" to follow up every lead generated by the controversial system of automatic number plate recognition (ANPR) cameras.

The Independent Police Complaints Commission (IPCC) called for a full review of the network, which has come under fire for creating a database containing billions of journeys.

The criticism was made after a review of the hunt for Peter Chapman, 33, who kidnapped, raped and murdered 17-year-old Ashleigh Hall on October 25, 2009, after posing as a teenager on Facebook.

Officials discovered three police forces missed 15 opportunities to capture the suspect, who was wanted for suspected arson, theft and breaching a sex offenders register order between October 23 and 26.

They said North Yorkshire, Cleveland and Durham forces showed "serious inconsistencies" in how they respond to hits generated by wanted offenders travelling through their patches.

Chapman’s blue Ford Mondeo car was caught on camera as he travelled around the North East after his details were added to a police "hotlist", with a medium priority, on October 23.

The IPCC found officers in North Yorkshire did not know they had registered two hits because they do not monitor the system 24 hours a day.

They found officers in Durham missed one hit because they were not logged in and a second was not picked up because cameras were not set up to monitor vehicles leaving the area.

In Cleveland, Chapman’s car was caught 12 times on seven cameras, all of which were assessed by a control room inspector who dispatched units on some occasions, finally catching Chapman on October 26 shortly after 5pm.

Chapman subsequently confessed to Miss Hall’s murder and led the police to her body. He admitted murder at Teesside Crown Court last March and was sentenced to life imprisonment.

Nicholas Long, of the IPCC, said the quality of information put into the Police National Computer "varies greatly", leading to an overload of information on the ANPR monitoring system.

He said: "This investigation has highlighted serious flaws in the operation of the ANPR system.

"It is clear that it can be a very valuable asset, but it is dependent on the system being managed and monitored well and containing accurate information."

"There needs to be a full review about how the ANPR system is operated, including the development of consistent policies for the monitoring of the system across all forces, the prioritisation of information and the accurate input of data."

Mr Long added: "The ANPR system is championed as a wonderful tool for police forces.

"However, it has undoubtedly become a victim of its own success in that the amount of information contained in the system and the hits generated has made it virtually impossible to monitor adequately, given police resources.